Cytokines play an important role in regulating the cellular response during inflammation and other immune functions. Of particular interest are the cytokines interleukin-1 (IL-1, .alpha. and .beta.) and tumor necrosis factor (TNF, .alpha. and .beta.), which are the intercellular proteins involved in the initial step of the inflammatory response cascade (Arai, et al., Ann. Rev. Biochem. 59: 783-836 (1990)). Thus, there has been a substantial amount of research recently devoted to interfering with the production of IL-1 and TNF in response to an inflammatory stimulus.
One therapeutic approach involves suppressing the production of IL-1 and TNF at the level of transcription and/or translation and/or secretion. The activities associated with certain of pyridinyl imidazoles led to a class of compounds referred to as "CSAIDs", or Cytokine suppressing Anti-Inflammatory Drugs (FIG. 1). These compounds appear to arrest the expression of IL-1 and TNF predominantly at the translational level, although a lesser effect on transcription has also been observed but effects on other steps cannot be ruled out.
The pyridinyl imidazole, 5-(4-pyridyl)-6(4-fluorophenyl)-2,3-dihydroimidazo(2,1-b)thiazole (SK&F 86002) was identified as the prototypic CSAID. The basis for its activity has been established and characterized (Lee, et al., Int'l. J. Immunopharm. 10(7): 835-843 (1988); Agents and Actions 27(3/4): 277-279 (1989) and Int'l. J. Immunother. 6(1):1-12 (1990)). SAR studies (discussed herein) suggest that cytokine suppressive effect of the pyridinyl imidazoles represents a unique activity independent of their inhibitory effects on eicosanoid and leukotriene production. However, no compound of the initial series was selective for cytokine suppressive activity or was particularly potent.
Since the CSAIDs have substantial potential as novel anti-inflammatory therapeutic agents, there is significant interest in characterizing their mechanism of action at the molecular level, as well as obtaining compounds with increased selectivity and potency. Specifically, identification and characterization of the CSAID molecular target would enhance the understanding of the biochemical processes involved in inflammation and aid in the design and screening of more potent anti-inflammatory drugs. This invention discloses, inter alia, the purification and characterization of such CSAID binding proteins (CSBPs).
The DNAs of this invention, such as the specific sequences disclosed herein, are useful in that they encode the genetic information required for the expression of the novel CSBPs. Additionally, the sequences may be used as probes in order to isolate and identify any additional members of the CSBP family as well as forming the basis of antisense therapy for disease conditions which are characterized by atypical expression of the CSBP gene. The novel protein itself is useful directly as a therapeutic or diagnostic agent as well as a component in a screening system for compounds which are antagonists or agonists of CSAID binding activity. The protein is also useful for eliciting antibody production in heterologous species, said antibodies being useful for the aforesaid diagnostic, therapeutic and screening applications. These and additional uses for the reagents described herein will become apparent to those of ordinary skill in the art upon reading this specification.